You know this means that Gilgamesh will have Ripple Skills and possess the Red Stone of Aja, all the Stone Arrows, and the Stone Masks right?

Stand : Good to be King or Named after some Babylonian God
Endursaga - the Herald
Ennugi - Attendant/Thronebearer (in the path that he would have had the First Stand and would have named it Stand (equivalent)
Hendursaga - minor God of Law
Kabta - obscure God lit. “Lofty One of Heaven”
Mummu - Primordial God of Crafts and technical skill. - power to have Mastery in any skill humans have prized. (Skill of all things to match ownership of all things.)

To one of the reviews below: not just anyone can have a Stand. The rules may be more lax compared to the ones regarding Nasuverse magic, but you do need to have some "potential" for it in JJBA too. Also, while they're still obviously different, Third magic is the easiest way to explain Stands in Nasuverse terms. Servants themselves are materialized spirits, the closest thing to a Stand from Nasuverse that I can think of off the top of my head, which is made possible by an limited application of the Third. While details obviously don't add up, compromises are necessary when making crossovers with such incompatible settings.

In other words, I think that the explanation given by author works well enough given the circumstances (this is pretty obviously an AU after all). I do hope there is more to Illya's Stand than simple necromancy though. And yes, the way she's being so upfront about Kiritsugu seems bit OOC too, but that's something I can still write off as just another AU element...

What's this, a Fate Stay Night and JoJo crossover.

This must be the work of an enemy stand!

Did I just see a Disney Reference? and I like it :)

...me likey. Straight into the action eh? Try to balance the overwhelming firepower awesomeness and the puzzle battles of jojo m'k?

So nothing too bad about this chapter, the worst things being that it's pretty void of detail and Illya is talking about Kiritsugu far too much. Some of the things you're doing with Stands, though, I do have to comment on. First, and this is the most minor of things, but Illya's Stand is just necromancy, and isn't that already something that any magus can do if they just study hard enough? Not really impressive, and it honestly doesn't suit her as a character. Then there's the fact that her and Berserker's Stands are named after songs from a musical and a Disney movie, respectively, and that's not how the Stand naming scheme works. Shirou's Stand also shouldn't be a woman because while there are examples of women having masculine Stands, there aren't any examples of men having feminine Stands. Finally, the explanation for how Stands operate in the Nasuverse makes no sense. If they were connected to the Third Magic, that would mean only a magus could have a Stand, but literally any Joe Schmoe can be a Stand user; hell, even a street can have a Stand! Plus, the meteor that the Arrows were forged from has been on Earth for 50,000 years, meaning that Stands have been a part of the world since the Age of Gods. It makes no sense to simply say that they're an offshoot of a Nasuverse concept.

Again, nothing inherently wrong with the story, but the way you're using Stands is completely off base.

Love the song references.

interesting concept

Ohhhh! Jojoverse and Nasuverse in one! Servant vs Stand! Stand vs Magecraft! Poses a mogollón! I Dreamed a Dream against Archer’s Stand! (If Shirou gained his powers due to Archer then his future counterpart gains part of his) Let’s be fabulous! And don’t forget Hamon and Vampires. Vampires created from Stone Masks are fundamentally different from Dead Apostles but the two kinds of undead are really dangerous... and to think two races of near-god-like power created both of them...